filter url slash reverse string replace for slash and apos to find items which include such char.

filter url slash.php

File:
contao3/system/modules/metamodels/MetaModels/ItemList.php

public function setFilterParameters($arrPresets, $arrValues)
{
  ...
  
  foreach ($arrProcessed as $key => $value) {
  $value = str_replace(array('-slash-', '-apos-'), array('/', '\''), $value);
  $arrProcessed[$key] = $value;
  }
  
  $this->arrParam = $arrProcessed;
  
  return $this;
}